There are many types of fences that can be used to keep various entities such as pets, livestock, equipment, and even people within certain locations or perimeters. The most common are physical barriers. There are also underground fences, which use buried wire as the fence perimeter. Various types of mechanisms or methods may be used to prevent these entities from going outside certain locations or perimeters. For example, a collar-worn device is used to train animals not to pass over the underground wire. Failure to comply gives the animals a negative feedback stimulus, such as an electrical shock. One problem with these fences, however, is that once the animal or other entities cross the fence perimeter, it will no longer receive the negative stimulus. As such, an animal can roam freely after the initial stimuli. Also, underground fences may require a complete circuit around a property and does not allow for complex designs for keeping pets out of, for example, a garden or pool area within the property. Also, the cost of installing such an underground system is high and once installed it is not easily modified.
Pet location and tracking solutions using satellite positioning systems (SPS), such as global positioning system (GPS), is a growing field. These technologies, however, do not allow complex three-dimensional (3D) mapping of an area to confine animals to a desired space. Further, conventional techniques do not compensate for SPS outages or unavailability, indoor tracking, and the like.